Algae: Applications in Removing Arsenic and Beyond

A 5000x magnification view of diatoms, a type of tiny algae. (Credit: from Jim Mikulak (The English Wikipedia) via Wikimedia Commons.) Scientists at Zhejiang University have recently published an improved method for removing arsenic from drinking water, which relies on chemically modifying the shells of a type of algae, called diatoms, to make the shells efficient “sponges” for soaking up arsenic. Modified diatom shells are unique in that they can be widely manipulated for applications in fields as diverse as medicine and materials science.

Despite their microscopic size, diatoms produce shells, called frustules, which have the potential to be manipulated for many uses and technologies. The shells are largely composed of silica, a compound that is very stable yet can be chemically modified to possess chemical properties that make them useful for various functions, including arsenic removal. A benefit of these shells is that they are naturally patterned to have a large surface area, meaning that there is a lot of working space to modify. Additionally, the shells are easily obtained; diatoms can be grown with little cost or effort to produce large amounts of shells that can then be modified.

In the cited study, shells were collected and then modified in a series of chemical reactions that are usually less than 100% efficient. However, one of the ultimate goals of diatom research is to be able to genetically engineer diatoms to produce modified shells themselves, a process that will be more efficient and sustainable. There is hope that modified frustules can be used not only for soaking up toxins, but also for drug delivery and catalyzing chemical reactions. The biggest limitation is our current lack of understanding of their biology, and how they control the shapes and patterns of their shells. Gaining this knowledge will aid in the development of better ways to manipulate diatom shell formation, expanding the efficiency of their application.

Managing correspondent: Emily Low

Acknowledgments: Special thanks to contributing correspondent Jernej Turnsek, a graduate student in the Biological and Biomedical Sciences program at Harvard, for providing expert advice on diatom research.

One thought on “Algae: Applications in Removing Arsenic and Beyond”

Hi Jernej,
Long time no see. Hope everything is good with your project.
I am recently thinking if gene-modified pattern of diatom replicas are required. Because the biosynthesized pattern on replicas is not very stable, such as the size of holes in micrometer level would not so precise. If silicas could be produced by industry, such as 3D print, the pattern on replicas would always be the same and keep stable. The pattern of replicas is important for industry production, which could provide different molds for noble metal coating.
So I would like to know your opinion about what is the sense for scientists to work on gene-modified patterned replica.